A trial that has come to be known as the Clearstream affair, pitting the former prime minister Dominique de Villepin against Nicolas Sarkozy, ended in Paris today, after four weeks of hearings featuring spies, allegations of dirty tricks, forged documents and ambition and treachery at the highest levels of the French state.

De Villepin, an aristocratic former diplomat and foreign minister and a part-time poet, known internationally for his pre-Iraq war speech to the United Nations, is accused of plotting to damage Sarkozy's political career by allowing documents falsely linking his rival to an alleged organised crime and kickback ring to reach judges investigating an arms deal dating from the 1990s.

The trial has received intense media coverage in France, sparked partly by the revelations from within the corridors of power, and partly by the sparring between the two politicians, rivals at the time of the alleged offences to succeed an ageing President Jacques Chirac as the head of the French right. The pair have never made any secret of their animosity.

However, De Villepin said today that he was not bitter and that he extended an "open hand" towards Sarkozy. Before the trial, he had been less conciliatory, saying that his rival had "promised to hang me from a butcher's hook".

Sarkozy – one of 40 plaintiffs who brought the case – has not been present at any hearings but has been represented by a lawyer who said his client was no different from "anyone in any trial". The president has avoided making any reference to the court proceedings apart from a single off-the-cuff comment describing the defendants as "the guilty". Sarkozy later said he regretted his words.

Public prosecutors have demanded that De Villepin receive an 18-month suspended jail sentence and a fine of €45,000 (£41,000). They argue that his offence was one of omission rather than commission in allowing information which he knew to be false to reach judges.

The two men accused of being at the origin of the plot – a senior defence executive and strategist, Jean-Louis Gergorin, and a Lebanese-born computer specialist, Imad Lahoud — face jail.

If De Villepin is cleared the trial could be the "trampoline" which relaunches his flagging political career, said Frédéric Dabi, of pollsters IFOP. If he is found guilty, it could be its "cemetery".

De Villepin said after today's hearing that he wanted "to turn the page … to look to the future … and to serve the French people in however they desire."

For Sarkozy, the wrong verdict could fuel charges of an authoritarian style of government that have grown louder in recent months after a series of controversial appointments and interventions.

Polls have revealed however that though coverage of the affair has been intensive, few French people have followed its extraordinary detail. "It is seen as something for the specialists, not something that touches the everyday concerns of people," said Dabi.

One peak of interest was when two of France's most senior spies were called as witnesses. However the trial has largely fuelled a deep cynicism about the nation's elite, and the exercise and abuse of power.